The purpose of this research study is to assess the development of some of the long-term complications of diabetes among volunteers who, between 1983 and 1993, participated in the Diabetes Control and Complications Trial (DCCT). Approximately 1,420 volunteers will be asked to participate in this study in up to 29 centers in North America. The overall goal of the study is to help determine factors that are associated with the development of kidney, large blood vessel, eye and nerve complications in diabetes. We also hope to identify how high glucose can alter lipoproteins which carry cholesterol and other types of fats in the bloodstream.